// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2010 Gael Guennebaud <gael.guennebaud@inria.fr>
//
// This Source Code Form is subject to the terms of the Mozilla
// Public License v. 2.0. If a copy of the MPL was not distributed
// with this file, You can obtain one at http://mozilla.org/MPL/2.0/.

#ifndef EIGEN_ASSIGNMENT_FUNCTORS_H
#define EIGEN_ASSIGNMENT_FUNCTORS_H

namespace Eigen {

namespace internal {

    /** \internal
  * \brief Template functor for scalar/packet assignment
  *
  */
    template <typename DstScalar, typename SrcScalar> struct assign_op
    {
        EIGEN_EMPTY_STRUCT_CTOR(assign_op)
        EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a = b; }

        template <int Alignment, typename Packet> EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const
        {
            internal::pstoret<DstScalar, Packet, Alignment>(a, b);
        }
    };

    // Empty overload for void type (used by PermutationMatrix)
    template <typename DstScalar> struct assign_op<DstScalar, void>
    {
    };

    template <typename DstScalar, typename SrcScalar> struct functor_traits<assign_op<DstScalar, SrcScalar>>
    {
        enum
        {
            Cost = NumTraits<DstScalar>::ReadCost,
            PacketAccess = is_same<DstScalar, SrcScalar>::value && packet_traits<DstScalar>::Vectorizable && packet_traits<SrcScalar>::Vectorizable
        };
    };

    /** \internal
  * \brief Template functor for scalar/packet assignment with addition
  *
  */
    template <typename DstScalar, typename SrcScalar> struct add_assign_op
    {
        EIGEN_EMPTY_STRUCT_CTOR(add_assign_op)
        EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a += b; }

        template <int Alignment, typename Packet> EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const
        {
            internal::pstoret<DstScalar, Packet, Alignment>(a, internal::padd(internal::ploadt<Packet, Alignment>(a), b));
        }
    };
    template <typename DstScalar, typename SrcScalar> struct functor_traits<add_assign_op<DstScalar, SrcScalar>>
    {
        enum
        {
            Cost = NumTraits<DstScalar>::ReadCost + NumTraits<DstScalar>::AddCost,
            PacketAccess = is_same<DstScalar, SrcScalar>::value && packet_traits<DstScalar>::HasAdd
        };
    };

    /** \internal
  * \brief Template functor for scalar/packet assignment with subtraction
  *
  */
    template <typename DstScalar, typename SrcScalar> struct sub_assign_op
    {
        EIGEN_EMPTY_STRUCT_CTOR(sub_assign_op)
        EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a -= b; }

        template <int Alignment, typename Packet> EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const
        {
            internal::pstoret<DstScalar, Packet, Alignment>(a, internal::psub(internal::ploadt<Packet, Alignment>(a), b));
        }
    };
    template <typename DstScalar, typename SrcScalar> struct functor_traits<sub_assign_op<DstScalar, SrcScalar>>
    {
        enum
        {
            Cost = NumTraits<DstScalar>::ReadCost + NumTraits<DstScalar>::AddCost,
            PacketAccess = is_same<DstScalar, SrcScalar>::value && packet_traits<DstScalar>::HasSub
        };
    };

    /** \internal
  * \brief Template functor for scalar/packet assignment with multiplication
  *
  */
    template <typename DstScalar, typename SrcScalar = DstScalar> struct mul_assign_op
    {
        EIGEN_EMPTY_STRUCT_CTOR(mul_assign_op)
        EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a *= b; }

        template <int Alignment, typename Packet> EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const
        {
            internal::pstoret<DstScalar, Packet, Alignment>(a, internal::pmul(internal::ploadt<Packet, Alignment>(a), b));
        }
    };
    template <typename DstScalar, typename SrcScalar> struct functor_traits<mul_assign_op<DstScalar, SrcScalar>>
    {
        enum
        {
            Cost = NumTraits<DstScalar>::ReadCost + NumTraits<DstScalar>::MulCost,
            PacketAccess = is_same<DstScalar, SrcScalar>::value && packet_traits<DstScalar>::HasMul
        };
    };

    /** \internal
  * \brief Template functor for scalar/packet assignment with diviving
  *
  */
    template <typename DstScalar, typename SrcScalar = DstScalar> struct div_assign_op
    {
        EIGEN_EMPTY_STRUCT_CTOR(div_assign_op)
        EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(DstScalar& a, const SrcScalar& b) const { a /= b; }

        template <int Alignment, typename Packet> EIGEN_STRONG_INLINE void assignPacket(DstScalar* a, const Packet& b) const
        {
            internal::pstoret<DstScalar, Packet, Alignment>(a, internal::pdiv(internal::ploadt<Packet, Alignment>(a), b));
        }
    };
    template <typename DstScalar, typename SrcScalar> struct functor_traits<div_assign_op<DstScalar, SrcScalar>>
    {
        enum
        {
            Cost = NumTraits<DstScalar>::ReadCost + NumTraits<DstScalar>::MulCost,
            PacketAccess = is_same<DstScalar, SrcScalar>::value && packet_traits<DstScalar>::HasDiv
        };
    };

    /** \internal
  * \brief Template functor for scalar/packet assignment with swapping
  *
  * It works as follow. For a non-vectorized evaluation loop, we have:
  *   for(i) func(A.coeffRef(i), B.coeff(i));
  * where B is a SwapWrapper expression. The trick is to make SwapWrapper::coeff behaves like a non-const coeffRef.
  * Actually, SwapWrapper might not even be needed since even if B is a plain expression, since it has to be writable
  * B.coeff already returns a const reference to the underlying scalar value.
  * 
  * The case of a vectorized loop is more tricky:
  *   for(i,j) func.assignPacket<A_Align>(&A.coeffRef(i,j), B.packet<B_Align>(i,j));
  * Here, B must be a SwapWrapper whose packet function actually returns a proxy object holding a Scalar*,
  * the actual alignment and Packet type.
  *
  */
    template <typename Scalar> struct swap_assign_op
    {
        EIGEN_EMPTY_STRUCT_CTOR(swap_assign_op)
        EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void assignCoeff(Scalar& a, const Scalar& b) const
        {
#ifdef EIGEN_GPUCC
            // FIXME is there some kind of cuda::swap?
            Scalar t = b;
            const_cast<Scalar&>(b) = a;
            a = t;
#else
            using std::swap;
            swap(a, const_cast<Scalar&>(b));
#endif
        }
    };
    template <typename Scalar> struct functor_traits<swap_assign_op<Scalar>>
    {
        enum
        {
            Cost = 3 * NumTraits<Scalar>::ReadCost,
            PacketAccess =
#if defined(EIGEN_VECTORIZE_AVX) && EIGEN_COMP_CLANG && (EIGEN_COMP_CLANG < 800 || defined(__apple_build_version__))
                // This is a partial workaround for a bug in clang generating bad code
            // when mixing 256/512 bits loads and 128 bits moves.
            // See http://eigen.tuxfamily.org/bz/show_bug.cgi?id=1684
            //     https://bugs.llvm.org/show_bug.cgi?id=40815
            0
#else
                packet_traits<Scalar>::Vectorizable
#endif
        };
    };

}  // namespace internal

}  // namespace Eigen

#endif  // EIGEN_ASSIGNMENT_FUNCTORS_H
